Increased wave action promotes muscle performance but increasing temperatures cause a tenacity-endurance trade-off in intertidal snails (Nerita atramentosa).

Samuel Clayman,Frank Seebacher,Paolo Domenici

doi:10.1093/conphys/coz039

Abstract

Concurrent increases in wave action and sea surface temperatures increase the physical impact on intertidal organisms and affect their physiological capacity to respond to that impact. Our aim was to determine whether wave exposure altered muscle function in intertidal snails (Nerita atramentosa) and whether responses to wave action and temperature are plastic, leading to compensation for altered environmental conditions. We show that field snails from exposed shores had greater endurance and vertical tenacity than snails from matched protected shores (n = 5 pairs of shores). There were no differences in muscle metabolic capacities (strombine/lactate dehydrogenase, citrate synthase and cytochrome c oxidase activities) between shore types. Maximum stress (force/foot area) produced by isolated foot muscle did not differ between shore types, but foot muscle from snails on exposed shores had greater endurance. A laboratory experiment showed that vertical tenacity was greater in animals acclimated for 3 weeks to cool winter temperatures (15C) compared to summer temperatures (25C), but endurance was greater in snails acclimated to 25°C. Acclimation to water flow that mimicked wave action in the field increased vertical tenacity but decreased endurance. Our data show that increased wave action elicits a training effect on muscle, but that increasing sea surface temperature can cause a trade-off between tenacity and endurance. Ocean warming would negate the beneficial increase in tenacity that could render snails more resistant to acute impacts of wave action, while promoting longer term resistance to dislodgment by waves.

Highlights

Environmental change is a principal selection pressure, and the complexity of natural environments means that animals often respond to changes in more than a single environmental driver at a time (Brierley and Kingsford, 2009)
We measured vertical dislodgement and endurance as described above for field experiments, Vertical tenacity was greater in snails from exposed sites (P = 0.024; Fig. 2B), but there were significant differences between sites
Activities of strombine/LDH, citrate synthase (CS), and c oxidase (COX) did not differ between snails from exposed and protected shores, but in all cases there were significant differences between sites

Summary

Introduction

Environmental change is a principal selection pressure, and the complexity of natural environments means that animals often respond to changes in more than a single environmental driver at a time (Brierley and Kingsford, 2009). Anthropogenic climate change has already led to increased temperatures, increased wind speed and increased wave heights in oceans (Aarnes et al, 2017; Hemer et al, 2013; Young et al, 2011), as well as to ocean acidification (Doney et al, 2009). Temperature changes alter physiological performance (James, 2013; Olberding and Deban, 2017), thereby modifying the impact of other drivers. The aim of this study was to determine whether plastic responses in muscle performance can compensate for the interaction between changing wave action and temperature in an intertidal organism (the gastropod Nerita atramentosa)

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